U.S. boss Bob Bradley has yet to run out the same line-up twice in this World Cup, a fact that leaves questions surrounding his 11 for Saturday's round of 16 clash with Ghana.

Several players are lock starters, and we can isolate the mystery spots through process of elimination.

Tim Howard will be in goal, the right side of the defense looks set for Steve Cherundolo and Jay DeMerit, with midfielder Michael Bradley in front of them and Jozy Altidore up top. Landon Donovan will take one wide spot and Clint Dempsey will be somewhere in attack.

Carlos Bocanegra's place in defense, though, is up in the air. Thanks to the Algeria shutout and Ghana's speed out wide, Bradley may keep the captain in the middle and Jonathan Bornstein at left back.

Then again, he may sacrifice Bornstein to bring Oguchi Onyewu back into the fold for a revenge outing against Ghana.

He could also bring Jonathan Spector in to close down the left side, but an identical backline to the one against Algeria seems most likely.

Moving into midfield, the race to be Bradley's partner seems to pit England starter Ricardo Clark against Algeria starter Maurice Edu. Ghana have speed up the middle and the coach will probably want to counter that.

If Bradley opts to spring a central midfield surprise, that would likely come in the form of Benny Feilhaber. The former UCLA walk-on has added that little something extra in his sub appearances.

Then there’s the Dempsey conundrum, which directly relates to the identity and location of the 11th man. The Fulham ace could be used up top, but Bradley thus far seems to prefer starting an active forward with Altidore.

This allows him to use Dempsey's midfield grit and ability to spark plays, with the option of sliding the Texan up front as the game unfolds.

Robbie Findley returns from a one-game ban, but might not be able to regain a starting place. Bradley could decide to give Edson Buddle his first World Cup start.

The Galaxy star can help Altidore soften up the Ghana back and offer a greater aerial threat. Then, quick feet options Findley and Herculez Gomez could enter to face the tiring defense.

However, if the coach does start Dempsey at forward, this opens up a wide place for the likes of Feilhaber, DaMarcus Beasley or Stuart Holden. Beasley's combination of experience, speed and freshness could give him an edge.